Protective Instrumentation and Shutdown Devices – Low Charge Flow
Safe operation also requires process flow through all tubes. Loss of flow through a tube:
• Will lead to rapid overheating and rupture of the tube
• Needs all fuel, including that for minimum fires, to be shut off automatically
A furnace fire represents a significant risk to personnel, environment, equipment and production. Also there normally are no independent backup devices to protect from low charge flow. For these reasons, dual sensors and shutdown logic are recommended; emergency shutdown valves would typically be double block and bleed valves for fuel gas and a single testable valve for fuel oil.